1. Field of the Invention
The present invention relates to a scanner system, applied to such as a scanning type probe microscope, for example, a scanning tunneling microscope (STM) and atomic force microscope (AFM), for scanning a probe and a sample relative to each other.
The "Method and Apparatus for Forming Image on Sample Surface" emerging, for example, in Jpn Pat. Appln. KOKAI Publication No. 62-130302 proposes a scanning type probe microscope, such as a scanning tunneling microscope (STM) and atomic force microscope (AFM), having a simple arrangement with a high length/width resolution in an atomic size level.
In order to achieve such a scanning probe microscope, a system is required which can accurately control a relative probe-to-sample position. Generally use has been made of a tripod- and a tube-type piezoelectric scanner using a piezoelectric body in a scanner system.
The tube type piezoelectric scanner (tube scanner) has a single common electrode on the inner wall surface and four, circumferentially spaced-apart, separate drive electrodes on the outer peripheral surface of the tube-like piezoelectric body. By applying voltages to the four electrodes under proper control, the free end of the piezoelectric body can be three-dimensionally displaced due to its bending, extension/contraction, etc. By fixing a stage to the free end of the piezoelectric body and supporting a probe or a sample on the stage, the sample is scanned by the probe through a displacement at the end of the piezoelectric body.
It is well known that the piezoelectric body manifests a phenomenon, such as a hysteresis, creeping, etc., upon displacement by a voltage drive. In the case where the probe or the sample is scanned by the piezoelectric scanner, the moving characteristic of the stage, that is, the probe or the sample, becomes nonlinear (voltage-displacement nonlinear characteristic). Such a nonlinearity emerges as a distortion in an observation image in the scanning type probe microscope, thus providing a bar to the quantitative measurement.